SAN FRANCISCO— The Center for Biological Diversity filed a lawsuit today against the U.S. Fish and Wildlife Service over the agency’s failure to protect the Sierra Nevada red fox as an endangered species under the Endangered Species Act. The Center petitioned for protection of the fox in 2011, but the agency has yet to make a final decision on its protection. The mountain-dwelling fox is one of the most endangered mammals in the world, with fewer than 50 individuals known to survive.

“It’s going to take an all hands on deck effort to save this gorgeous fox from extinction, but that effort won’t get going until the fox is granted the effective protection of the Endangered Species Act,” said Tierra Curry, a conservation biologist at the Center for Biological Diversity.

Sierra Nevada red foxes live in remote, high mountains in the Sierra Nevada and Cascade ranges south of the Columbia River. The fox has undergone drastic population decline due to logging, grazing, poisoning, trapping and off-road and over-snow vehicles. Climate change is projected to shrink the fox’s habitat even more dramatically as warming pushes the animal farther up mountain slopes.

Only two California populations of Sierra Nevada red foxes are known today. One, near Lassen Peak, includes only 20 breeding foxes. Eight foxes have been confirmed on Sonora Pass since 2010, when a population was discovered there. In 2011 and 2012 photos near Crater Lake, Sparks Lake and Mount Hood in Oregon captured images of what are thought to be Sierra Nevada red foxes.

Active at night, Sierra Nevada red foxes den in earthen cavities, winter in mature forest and summer in high meadows, fell fields, talus slopes and shrub lands. Their diet consists of rodents, small mammals, fruit, birds, insects and carrion. They are born into one of three color phases (red, black or cross) and are distinguishable from other native foxes by their black-backed ears and white-tipped tails.

The fox is one of 10 species across the country that the Center is prioritizing for Endangered Species Act protection this fiscal year. Under a settlement agreement with the Service that expedites protection decisions for 757 species, the Center can push forward 10 decisions per year. The other priority species for 2013 include two birds, two amphibians, two reptiles, a fish and two freshwater invertebrates. The species are facing extinction for many reasons, chief among them habitat loss, pollution, and sea-level rise from climate change. They include a New England songbird, the hellbender salamander, the Florida Keys mole skink, Suwannee moccasinshell mussel, Panama City crayfish, MacGillivray’s seaside sparrow, boreal toad, bridled darter, and critical habitat for the loggerhead sea turtle.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 500,000 members and online activists dedicated to the protection of endangered species and wild places.